An objection asks why the dependence of each member also requires a distinct cause of the collection. Does a totality possess some additional reality, or is it only the members considered together?
The argument need not imagine a separate material object called “the collection.” Its concern is a series whose members explain themselves only through other dependent members. The issue is whether this constitutes a complete account of existence.
Recognizing this objection is part of understanding the reasoning. Moving from the dependence of each member to a ground beyond all members requires justification, not just a definitional slogan.